1. Field
The present embodiments discussed herein relate to a wireless power supply system. In particular, the present embodiments relate to a control apparatus to transmit power in the wireless manner.
2. Description of the Related Art
In a known wireless power transmitting system, a power transmitting apparatus transmits power in the wireless manner to a power receiving apparatus using an electromagnetic wave. The power receiving apparatus converts the received electromagnetic wave into power and supplies the resultant power to a power consuming device or circuit in the power receiving apparatus.
In a known wireless power supply system, a position and orientation detecting unit detects the position and orientation of a receiving antenna and transmits information concerning the detected position and orientation to a controller of a power transmitting apparatus. The controller determines control target values of, for example, the magnitudes, phases, and frequencies of currents flowing through transmission coils so as to optimize the intensity of a magnetic field generated or received in the position and orientation of the receiving antenna, and performs control so that currents having values equal to the control target values flow through the transmission coils via driving circuits. Thus, the receiving antenna may be supplied with power with efficiency at all times.
As a well-known wireless power transmitting system, a wireless sensor system including a wireless sensor unit and a sensor signal receiver has been known. The wireless sensor unit includes a sensor section detecting a target of detection, a sensor signal transmitting section transmitting a sensor signal output from the sensor section in a wireless manner, and a power supply section. The power supply section of the wireless sensor unit includes power generating means and a power receiving portion which receives driving power wireless-transmitted. The wireless sensor unit further includes a power supply monitoring section. When power produced by power generation is insufficient, the wireless sensor unit transmits a power shortage signal, thus allowing wireless power supply. The above-described known systems are discussed in, for example, Japanese Unexamined Patent Application Publication No. 2008-283789 and No. 2005-100164.
As another wireless power transmitting system, there has been known a capsule endoscope system including an external unit which includes a transmitting antenna, a receiving antenna for receiving power transmitted by the transmitting antenna, a capsule endoscope which includes a receiving circuit section and a capsule endoscope functioning section. In the capsule endoscope system, a capsule endoscope includes a received power detecting unit that detects power received by the receiving antenna and an imaging rate controller that changes the rate of imaging by the capsule endoscope. When received power detected by the received power detecting unit is lower than a preset threshold value, the imaging rate controller reduces the imaging rate. Consequently, the capsule endoscope may be controlled so that the endoscope does not stop operating even if the efficiency of receiving power supplied from the wireless power supply system is lowered (refer to Japanese Unexamined Patent Application Publication No. 2008-284160).
In a known intra-subject information acquiring system, a remaining-power recognizing circuit included in a capsule endoscope recognizes the amount of remaining power of the capsule endoscope and superimposes information indicating the amount of remaining power on a transmission signal. An RF transmitter in the capsule endoscope transmits the transmission signal to a receiving apparatus on the outside of a subject. A remaining-power detecting circuit included in the receiving apparatus detects the information indicating the amount of remaining power. A display unit of an external apparatus displays the detected information (refer to Japanese Unexamined Patent Application Publication No. 2007-61191).